Rolling device for tube bending machine



April 17, 1962 s. WILMAN 3,029,668

' ROLLING DEVICE FOR TUBE BENDING MACHINE Filed Deo. 51, 1958 s sheets-sheet 1 i l in INVENTOR slclsMo/v w/LMAN @y a-Wm A TToR/vf ys' April 17, 1962 s. WILMAN 3,029,668

ROLLING DEVICE FOR TUBE BENDING MACHINE I Filed Dec. 3l, 1958 3 Sheets-Sheet 2 NvENToR ATTORNEYS April 17, 1962 s. WILMAN 3,029,668

ROLLING DEVICE FOR TUBE BENDING MACHINE Filed Dec. 31, 1958 E sheets-'sheet E Q l 8 A l/VVENTOR SIGSMOND W/LMN B5 Maw United States Patent O 3,029,668 ROLLING DEVICE FOR TUBE BENDNG MACHINE Sigismond Willman, 1-3 Rue dEvreux,

Courbevoie, France Filed Dec. 31, 1958, Ser. No. 7S4,291 Claims priority, application France Jan. 4, 1958 13 Claims. (Cl. Sil-11) The present invention relates to machines for the cold bending of vtubes of relatively large diameter -by means of a rolling pressure applied to the walls of the tube about an axis eccentric relative to the tube axis, whereby the tube wall portion located on the side of the outer arc of curvature of the bent tube is thinned out by the rolling pressure without appreciably altering the thickness of the opposite portion of the tube wall.

Thus, the rolled wall portion is elongated considerably along the outer are of curvature of the bent portion whereas the metal displacement along the inner arc of curvature is practically nil. The elongation of the outer arc relative to the inner arc determines the radius of curvature which depends only on the depth of the rolling pressure applied thereto. Under these conditions by adjusting the depth of said rolling pressure it is thus possible with the same rolling means to obtain any desired radius of curvature.

In the simplest machines this adjustment is accomplished when the machine is inoperative by changing the eccentric pivot pin of the rolling wheel. However in more improved machines of this character the radius of curvature of the workpiece may be adjusted at will during the operation of the machine. Y

ln spite of the reduction in thickness of the tube wall the mechanical strength of the tube is not impaired for two reasons: iirstly, the rolling pressure hardens the metal and therefore improves its strength resistance, and independently of this feature, the ultimate tensile strength measured along a circular arc is definitely higher than that measured along the generatrix of a cylindrical hollow body.

Notwithstanding the indisputable advantages resulting from this method of bending tubular parts by rolling, the machines hitherto proposed for the cold bending of tubes by the eccentric rolling method had a few drawbacks and it is the object of this invention to avoid these drawbacks by providing an improved rolling pressure tube bending machine having an improved rolling head.

More specifically, in former machines of this type the rolling pressure depth as defined hereinabove could be adjusted through thetmedium of two separate devices with one device to adjust the distance between the axis of the tube to be bent and the axis of the rolling circle, and the other device to alter at will the length of the rolling radius, so that the sum of the total displacements effected by the two devices was equal to the depth of the rolling pressure applied to the tube Wall.

Now this operationV is improved and simplified according to this invention by eliminating the two adjustment defined in the preceding paragraph and substituting therefor a single device whereby the desired rolling depth may be obtained directly, as will be made clear hereinafter.

To this end, the wheel-carrying head of the device according to this invention comprises at least two wheels, i.e. a rolling wheel and a bearing wheel.

rl`he contour of the rolling wheel is convex in order to engage the tube wall with a relatively reduced contact area while the bearing wheel or Wheels is or are cylindrical in order to bear with the whole of their axial length or generatrices against the tube wall.

Registering or co-planar with the rolling wheel is at least one bearing wheel and the distance between the two 3,029,b68 Patented Apr. 17, 1952 ice opposing wheels varies periodically at each revolution of the wheel-carrier, with the maximum distance being obtained when the rolling Wheel is on the outer arc of curvature, i.e. at the place where the rolling pressure is deepest, whereas the minimum distance between the two opposing wheels corresponds to the moment when the rollv ing wheel passes through the inner arc of curvature of the bent tube.

Of course, any number of wheels may be provided, according to the size of the tube to be bent. The example shown in the appended drawings and to which reference will be made hereinafter comprises a rolling head carrying one rolling wheel and two bearing wheels. This deice is characterized in that the distance between the plane passing through the axes of the two bearing wheels and the axis of the rolling wheel varies cyclically at each revolution of the wheel-carrying head in the same manner as the distance between the axes of the two wheels varies if only one bearing wheel is provided for co-acting with the rolling wheel. The variation in the distance between the opposing wheels may be obtained in different ways, for example by using mechanical means such as eccentric members, gearings or other mechanical members, or hydraulic means, and the like.

The typical form of embodiment described hereafter employs a system of eccentrics which is very simple and easy to operate. In any case, this form of embodiment should not be construed as precluding the use of other methods of producing the cyclical variation in the distances between the wheels in the specific modilications contemplated.

in the present device, an eccentric portion of the pivot pin which carries the rolling wheel can be either xed'or variable in direction. `In the iirst case, the eccentric portion is always directed towards the tube generatrix forming the external arc of curvature. In the second case, the variation of the eccentric portion is obtained by any angular oscillation of said pivot pin which carries the rolling wheel with respect to the angular position of the wheel carrying head.

In order to afford a clearer understanding of the present invention and of the manner in which the same may be carried out in the practice, reference will now be made to the accompanying drawings illustrating diagrammatically by way of example a typical -form of embodiment of the invention, concerning the above mentioned second case.

In the drawings: 4

1FIGURE 1 is alongitudinal axial section of a tube portion during the bending thereof by means of a rolling head constructed according to the teachings of this invention; v

FIGURE 2 is a cross-section of the rolling headinserted in the tube to be bent, and

FiGURES 3 and 4 are an axial section and a cross-spection, respectively, showing the adjustment control device' suitable for the form of embodiment shown in FIGS. l and 2.

FIG. 5 is a longitudinal axial section of a tube portion having a double universal joint therein.

The rolling head 1 according to the form of embodiment of this invention, which is illustrated in FIGS..1 and 2, consists of a cylindrical body formed with cavities adapted to receive the rolling wheel 2 and the bearing wheels 3 mounted for free rotation on needle bearings centered on corresponding pivot pins 4 and 5.

The shaft or pivot pin 4 is formed with an eccentric portion 6 on which the rolling wheel 2 is mounted with a The direction of the eccentric part 6 of the pivot pin 4 can be maintained always the same during the rotation of the wheel carrying head, for example by a gearing between a fixed central shaft and said pin. However there will be described hereinafter a modification according to vwhich the pin 4 receives a periodic angular oscillation during the rotation of the wheel carrying head.

The tube 7 to be bent is inserted through the tube steady (not shown) consisting for example of a pair of jaws adapted to act as a supporting member for the tube wall portion to be rolled by the wheel 2.

The adjustment of the rolling depth of rolling wheel 2 is effected by altering the amplitude of the cyclical angular displacement of the wheel-carrying shaft 4 with this change occurring upon each revolution of the wheel` carrying head. Thus, notably, if no angular oscillation takes place, no rolling pressure will be applied and the greater the angle of oscillation, the deeper the rolling ypressure provided by the device.

The mean angular' Velocity of the central shaft '8 is exactly the same as that of the wheel carrying head 1. In other words, for each complete revolution of the former there corresponds a complete revolution of the latter, since they rotate bodily.y However, the central shaft 8 accomplishes an angular swinging movement relative to the wheelfcarrying head i rotating at a constant speed. This swinging movement or oscillation is transmitted through pinions 9 and 10 to the pivot pin 4 of which the eccentric portion 6 causes the rolling wheel 2- to be periodically moved towards the wall 7 to be rolled with this movement occurring at each revolution of the wheel-carrying head when the rolling wheel moves at right angles across the tube generatrix which is to constitute, upon completion of the rolling operation, the outer arc of curvature of the bent tube. Y Y

When the rolling wheel 2 is on the opposite side, that is, on the generatrix which is to constitute, upon completion of the rolling operation, the inner arc of curvature of the 'bent tube, it does not bear against the tube wall since the reverse movement of the eccentric portion 6 of pivot pin 4 has caused this rolling wheel to move away from this wall. In other words due tothe oscillation of the eccentric portion 6 the maximum rolling depth of wheel 2 isattained at each revolution and all the points corresponding to the maximum rolling depth of said wheel are spaced longitudinally on the line which is to constitute the outer arc of the bent tube.

To sum up, if the angle of oscillation of the eccentric portion 6 of the pivot pin 4 is approximately zero, the tube will not be rolled and bent, and therefore a straight tube will be obtained. If this angle is increased the rollingdepth of wheel '2 is increased accordingly.

In the form of embodiment illustrated the oscillation is transmitted from the central shaft 8 through pinions 9 and 10 to the eccentric portion 6, but it is possible to transmit this movement through flexible means such as a double universal joint composed of shaft 80 and universal joints 81 and 82 connected thereto (see FIG. 5) and interconnecting the end of the oscillating central shaft 8 andthe relevant end of the eccentric wheel-carrying shaft 4 to which this oscillation is to be transmitted.

FIGURES 3 and 4 illustrate the device provided for producing the angular oscillation of the central shaft 8 forming part of the device described hereinabove and illustrated in FIGS. l and 2. The purpose of this further device is to permit the adjustment of the amplitude of oscillation of the central shaft 8. To this end, a cylindrical case 61 is mounted at the machine end opposite to that carry-ing the rolling head with this case supporting through its center an end of a shaft62 iixedly connected with thel central shaft 8 through which the swinging movement isA to be transmitted to the pivot pin 4 carrying the rolling wheel 2.

' A crank 63 is iixedly connected to shaft 62 and is also connected in turn through the medium of a pivotpin 64 to an end of an extensible link 65. The length of this link 65 may be increased or decreased at will by rotating a left-hand and right-hand adjustment nut 66, so that the device may be adapted exactly to the inner diameter of the tube to be bent. The other end of the link 65 carries a follower 67 and is connected through pivot pins 7i and 72 and a link 70 to the outer end of a crank 68 fixedly connected to or formed integrally with the main hollow shaft 69 lixedly connected to the rolling head 1.

This assembly of two links 6,5 and 70 and two cranks 63 and 68, having a fixed axis 73 and three pivot pins 64, 71 and 72, constitutes a deformable quadrilateral of which the four sides will not vary in length during the rotation about the axis 73, only their angles being changeable. Thus, the variation in these angular Values is obtained by moving the pivot pin 71 towards or away from the axis 73. For example, by moving the pivot pin 71 towards the axis 73 the angle formed between the cranks 63 and 68 is increased, and if the change occurs in the opposite direction this angle is reduced. Thus, the central shaft 62 may be caused to accomplish a cyclical and limited angular movement within the main shaft 69 and since the former transmits its oscillation to the wheelcarrying eccentric portion 6 it is clear that it is a very simple matter with this mechanism to gradually vary the rolling depth of wheel 2 from one point to another of the rolled periphery of the tube.

When the operator wishes to obtain a cyclical variation in the distance between the movable point 71 and the fixed point 73, he simply causes the movable point 71 to describe a circle having its center shifted in relation to the xed point 73.

If the minimum distance between these two points is stationary, the amplitude of the angular oscillation of the central shaft 62 in relation to the main shaft 69 will constantly have the same value, and consequently the rolling depth measured along the outer arc will remain unchanged, so that the radius of curvature of the tube will also remain constant.

This radius of curvature may be changed during the operation of the tube bending machine by simply altering the angle of oscillation of the wheel-carrying eccentric and therefore, the angle of oscillation of the central shaft 62. To this end, the variations in the amplitude of the distance between the aforesaid points 71 and 73 mustl be acted upon. In other words, it is suiiicient to control thev throw of the axis of the circle described by point 71 in relation to the fixed point 73.

If nor throw exists, no rolling action will occur. As the throw between the path of the movable point 71 and the fixed point 73 increases, the rolling depth is increased accordingly.

The practical actuation of this movement is evidenced in FIG. 3 of the drawings in which the cylindrical case 61 has slidably fitted therein a movable annular cam 74 adapted to be moved in the axial direction in relation to the stationary case 61. This movement may be eected by means of a screw 75 controlled by a handwheel 76. One portion 77 of the inner wall of this movable cam 74 is tapered and the axis of this portion 77 is inclined in relation to the axis 73 of the central shaft 62 of the machine.

Since the follower 67 having its axis positioned at 71 rolls inside the cam 74, the inclination of the axis of this cam constitutes a practical means for altering at will the throw by displacing axially the cam 74 within the outer stationary case 61. As shown, this displacement may be effected byl rotating the` handwheel 76 in the proper direction.

In the relative position of the parts which is shown in the drawings the throw is maximum since the follower 67 is positioned as near as possible to the axis 73 of shaft 62. If the operator displaces the movable cam 74 to the right (FIG. 3), the distance between the follower 67 and the axis 73 of shaft 62 is increased and when the follower engages the point of cam 74 which is the remotest from the axis 73, the latter becomes coincident with the center of the rotational path of follower 67, so that the angular oscillation is nil. Therefore, no rolling action is exerted in this case by the eccentric pivot pin since the throw is also nil.

For bending a tube, the operation is always started from point zero, that is, with zero throw. Then, as the tube to be bent is fed through the tube steady, the handwheel 76 is rotated to pull the inner movable cam 74 to the left-hand side of FIG. 3, that is to the rear of the machine, and stopped in the position corresponding to the desired radius of curvature by which the tube is to be bent.

The follower 67 is urged by the centrifugal force or by spring means (not shown) against the inner tapered face of the movable cam 74.

Of course, constructional details, relative proportions and arrangement of the parts illustrated may be varied in the single form of embodiment shown and described herein, without however departing from the basic principles of the invention as set forth in the appended claims.

I claim:

.1. A device for bending tubes comprising a wheelcarrying head capable of rotating inside the tube to be bent, a roll wheel rotatablymounted on said head and extending laterally from one side thereof, at least one bearing wheel rotatably mounted in said head and extending laterally from an opposite side thereof, said rolling wheel and bearing Wheel each being positioned on said head for at times bearing against an opposite portion of the inner surface of said tube to the other wheel, said rolling wheel having a convex periphery capable of penetrating into the tube, said bearing wheel having a relatively large surface resistant to the penetra-tion of said tube, and means for moving said rolling wheel relative to said head for varying the distance between the 4axes of said rolling wheel and said bearing wheel at each revolution of said head with said distance being at its maximum when said rolling wheel passes through the axial plane of said tube which contains the generatrix providing the outer arc of curvature and being at its minimum when said head has been rotated through 180 in relation to the tube axis from said maximum position of said rolling wheel passing across the axial plane containing the tube generatrix constituting the inner arc of cur vature of said tube.

2. A device for bending tubes as claimed in claim 1, wherein a pin having an eccentric portion is rotatably mounted in said head and connected to said means for Y being rotated thereby and said rolling wheel is mounted on said eccentric portion which portion has the throw thereof directed towards the tube generatrix constituting the outer arc of curvature of the bent tube.

3. A device Vfor bending tubes as claimed in claim l, wherein a pin is rotatably mounted in said head and has an eccentric portion with said rolling wheel mounted on said eccentric portion and said means is connected to said pin Vfor causing said pin to oscillate angularly while said head is rotated at a uniform speed.

4. A device for bending tubes as claimed in claim 1, wherein a pin is rotatably mounted on said head and has as eccentric portion with said rolling wheel mounted on said eccentric portion, a shaft is connected to said means and is given oscillations thereby for determining the amplitude of the variationsin the distance between the axes of said rolling wheel and said bearing roller and further means operatively connects said shaft to said pin whereby said rolling wheel is given said oscillations.

5. A device for bending tubes as claimed in claim l, wherein a pin is rotatably mounted on said head and has an eccentric portion with said rolling wheel mounted on said eccentric portion, a shaft is connected to said means and is given oscillations thereby for determining the 6 amplitude of the variations in the distance between the axes of said rolling wheel and said bearing roller and gearing connects said shaft and said pin whereby said rolling wheel is given saidoscillations.

6. A device for bending tubes as claimed in claim 1, wherein a pin is rotatably mounted on said head and has an eccentric portion with said rolling wheel mounted on said eccentric portion, a shaft is connected t0 said means and is given oscillations thereby for determining the amplitude of the variations in the distance between the axes of said rolling wheel and said bearing roller and universal joints connect said shaft and said pin whereby said rolling wheel is given said oscillations.

7. A device ifor bending tubes as claimed in claim l,l

wherein said means consists of a pair of cranks, a pair of links pivotally connected together and to said cranks to provide a deformable quadrilateral, a rotatable shaft connected to said quadrilateral and forming a fixed pivot for one angle of said quadrilateral, means for moving the opposite angle of said quadrilateral to and from said fixed pivot at each revolution of said shaft to deform said quadrilateral and thereby rotate said shaft, an eccentric pin rotatably mounted on said head and having said rolling wheel mounted thereon and means operatively connecting said shaft and said pin.

I8. A device for bending tubes as claimed in claim 1, wherein said means consists of a pair of cranks, a pair of links pivotally connected together and -to said cranks to provide a deformable quadrilateral, a rotatable shaft connected to said quadrilateral and forming a fixed pivot for one angle of said quadrilateral, means for moving the opposite angle of said quadrilateral to and from said fixed pivot at each revolution of said shaft 4to deform said quadrilateral and thereby rotate said shaft, an eccentric pin rotatably mounted on said head and having said rolling wheel mounted thereon and means operatively connecting said shaft and said pin, said moving means consists of a roller rotatably connected to said opposite angle of said quadrilateral, a cam having said roller in engagement therewith and a portion with an inner tapered surface whose axis is inclined in relation to the axis of said shaft.

9. A device for bending tubes as claimed in claim l, wherein said means consists of a pair of cranks, a pair of links pivotally connected together and to said cranks to provide vdeformable quadrilateral, a rotatable shaft connected to said quadrilateral and forming a fixed pivot for one angle of said quadrilateral, means for moving the opposite angle of said quadrilateral to and from said rlixed pivot at each revolution of said shaft to deform said quadrilateral and thereby rotate said shaft, an eccentric pin rotatably mounted on said head and having said rolling wheel mounted thereon and means operav tively connecting said shaft and said pin, one of said links of said quadrilateral being adjustable as to length for permitting adjustment of said rolling wheel to tubes of various internal diameters.

l0. A device for bending tubes as claimed in claim 1, wherein said means consists of a pair of cranks, a pair of links pivotally connected together and to said cranks to provide a deformable quadrilateral, a rotatable shaft connected to said quadrilateral and forming a fixed pivot for one angle of said quadrilateral, means for moving the opposite angle of said quadrilateral to and from said fixed pivot at each revolution of said shaft to deform said quadrilateral and thereby rotate said shaft, an ec centric pin rotatably mounted on said head and having said rolling wheel mounted thereon and means operatively connecting said shaft and said pin, a hollow shaft concentrically supporting said head at one end and has one of said cranks connected thereto at its opposite end, and said rotatable shaft being co-axial with said hollow shaft and having the other of said cran-ks connected theret0.

11. A device for bending tubes as claimed in claim l,

. 7 t o wherein said means .consists of a pair of cranks, a pair of links pivotally connected together and to said cranks to provide a deformable quadrilateral, a rotatable shaft connected to said quadrilateral and forming a fixed pivot for one angle of said quadrilateral, means for moving the opposite angle of said quadrilateral to and from said axis of said shaft, said cam is displaceable co-axially of said shaft for displacing said roller relative to said fixed pivot.

l2. A device for bending tubes as claimed in claim l, wherein said means consists of a pair of cranks, a pair of links pi-votally connected together and to said cranks to provide a deformable quadrilateral, a rotatable shaft connected to said quadrilateral and forming a fixed pivot for one angle of said quadrilateral, means for moving the opposite angle of said quadrilateral to and from said fixed pivot at each revolution of said shaft to deform said quadrilateral and thereby rotate said shaft, an eccentric pin rotatably mounted on said head and having said rolling wheel mounted thereon and means operatively connecting said shaft and said pin, said moving means consists of a roller rotatably connected to said opposite angle of said quadrilateral, "a cam having said roller in engagement therewith and a portion with an inner tapered surface whose axis is inclined in relation to the axis of said shaft, a housing has a threaded opening and said cam slidably mounted therein for movement co-axially of said shaft, a threaded rod is connected to said cam and is in threaded engagement with said housing opening and means are provided for rotating said rod.

13. A device for bending tubes as claimed in claim l. wherein said means consists of a pair of cranks, a pair of links pivotally connected together and to said cranks to provide a deformable quadrilateral, a rotatable shaft connected to said quadrilateral and forming a fixed pivot for one angle of said quadrilateral, means for moving the opposite angle of said quadrilateral to and from said fixed pivot at each revolution of said shaft to deform said quadrilateral and thereby rotate said shaft, an eccentric pin rotatably mounted on said head and having said rolling wheel mounted thereon and means operatively connecting said shaft and said pin, said moving means consists of a roller rotatably connected to said opposite angle of said quadrilateral, an annular cam has has an offset circular inner surface which has a tapered portion whose axis is inclined in relation to the axis of Said shaft, said roller engages said cam inner surface,`a housing has said cam slidable therein co-axially of said shaft and means are provided for moving said cam coaxially of said shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,901,930 Wilman Sept. l, 1959 FOREIGN PATENTS 1,158,463 France lan. 27, 1958 

